Businesses get charged anywhere between 2.25% - 4% for cc transactions, depending on their service and the type of card used. Certain establishments want to roll their costs on to you. While horrible business practice in the N.A, margins are small here. You can get your fee waived but it is an incredible hassle and really not worth the time spent. Just bring as much cash as you feel safe with and everyone will be happy.
I don't levy a credit card surcharge. That said, it's more complicated than this post suggests. Like many businesses I need US$ to buy things, and when I accept a credit card I get the money in Bz$. Getting US$ from Bz$ is neither simple nor cheap. The true cost to me of accepting a credit card is in excess of 7%.